Rotary machines



J. M. CLARKE Dec. 8, 1970 ROTARY MACHINES 6 Sheets-Sheefl 5 Filed Oct. ll, 1968 B WW' I- Mm A torneya Dec. 8, 1970 J. M. cLARKE 3545399 V RoTARY MAcnINEs Filed om. 11, 1968 6 sheets-sheet 2 FIG. 3.

um Inventar- Atzrneys Dec. 8; 1970 J. M; CLARKE ROTARY MACHINES -e :meets-sheet 4 Filed 00'0. ll, 1968 FIG. 6.

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lnventar ttorney s Dec. 8,11970v Filed Oct. 1968 so S2 J; M. CLRKE ROTARY MACHINES FIG. 7.

6 Sheets-Sheet 5 /ssd FIG.- s.

De. 8,*1970 J. m-vcLARKE I I 3545399v ROTARY MACHINES Filed Oct. '11, 1958 s Sheen-sheet s *Jm W M Inventar- BY WW v WW ttorneys United States Patent O U.S. Cl. 418-68 13 Claims ABSTRACT OF THE DISCLOSURE A casing comprises -two end housings having flat surfaced faces inclined towards each other and joined at their peripheries fby a ring housing so as to define a circumferentially convergent-divergent channel within the casing which encloses a disc-like rotor. The rotor is coupled to two shafts, which are inclined relative to each other at the same angle as the flat faces, to form a variety of Hookeis joint so that the rotor will sweep over the channel in the casing during rotation. Lobes on the faces of the rotor bear against the sides of the channel (i.e., the flat faces of the end housings) at all times to define cham-bers whose volumes are varied during rotation. By suitable placing of ports in the channel, the machine can operate as an engine or a pump. In a variation, the, casing is in two parts rotatable relative to each other and arranged so that the angle between the two shafts is varied by such rotation.

In another variation, two rotor and casting assemblies are connected through a common shaft to achieve balancing yof thrust and inertal loads. Ports are arran'gcd to enable the machine to operate as an air Compressor with high rotational speeds; rotor and casing have conical side surfaces.

The invention relates to rotary piston machines.

Prior co-pending patent application Ser. No. 672,871 (Pat. No. 3,4'85218) is concerned with rotary piston machines which lend themselves to the provision of relatively sealing arrangements between a rotor and its encompassing casing.

The specification of the said prior application discloses various embodiments comprising a casing, a shaft having an oblique portion and a substantially disc-like rotor mounted co-axially on the said oblique portion on a bearing which permits the rotor to rotate separately from the shaft. The c-asing contains at least one annular channel of convergent-divergent configuration enclosing an annular part of the rotor and, by the provision of suitable gearing between the rotor and the shaft, a rotary oscllation movement is imparted to the rotor whereby a series of chambers formed between the said annular part of the rotor and the casing are yvaried in volume during continuous rotation of the rotor while points on the said part of the rotor remain in colse proximity to the casinlg7 to maintain sealing surfaces between the Chambers.

The present invention can reproduce a similar motion in a rotor without the use of gearing and maintain adequate sealng between rotor and casing without necessarily resorting to the use of 'resilient seals.

A rotary piston machine according to the invention includes a casing, two shafts mounted for rotation relative to the casing and inclined relative to each other, a rotor pivotally connected to the shafts about orthogonal diametral axes in such manner that the shafts constrain the rotor to move so that one diametral axis rotates in a plane normal to one shaft and the other diametral axis rotates in a plane normal to the second shaft, an annular channel within the casing bounded in part by two lateral walls set apart from each other at a distance which varies continu- 3,545,899 Patented Dec. 8, 1970 ously circu-mferentially in relation to the channel, an annular part of the yrotor contained within the channel, the radially outer portion of the rotor reduced in cross-section from its periphery inwardly towards the center of the rotor and constituting said annular part, and ports for the entry and ext of a working .fluid provided in the channel, whereby in operation fluid 'passing through one port is at high pressure compared vwith fluid passing through another por-t and the high pressure port is located in the periphery of the channel where the lateral walls are closest together.

In a preferred form of the invention, the rotor is connected separately to each shaft through trunnion-bearings.

In one form of the invention, the casing is in two parts which are -rotatbale relative to each other and arranged so that the angle betwen the shafts is varied by such rotation.

In another form of the invention, two rotors are connected to acommon shaft.

Various embodiments of the -invention will now be described by way of example with reference to the accompanying diagrammatic d-rawings, of which:

FIG. 1 is a longitudinal section of a rotary piston machine,

FIG. 2 is an elevation of a rotor forming a part of the lmachine of- FIG. l,

FIG. 3 is an elevation of the rotor looking in the direction of the arrow A in FIG. 2,

FIG. 4 shows the internal surfaces of the casing of the machine of FIG. 1,

FIG. 5 is a representation of a Hooke's joint,

FIG. 6 is a longitudinal section of a mo-dified form of casing,

FIG. 7 is a plan view of another rotary piston machine having two ro-tors,

FIG. 8 is a longitudinal section of the machine of FIG. 7,

FIGS. 9, and are illustrative of the geometry of the internal surfaces of a rotor casing in the machine of FIG. 7, FIG. -10 being a view looking in the direction of the arrow B in FIG. 9,

FIG. 11 is a similar vie-w -to FIG. 3, on a reduced scale, of a rotor of the machine of FIG. 7,

FIG. 12 is a part-sectioned view taken on the line XII-XII in FIG. 11, and

FIG. 13 is an elevation looking in the direction of the arrow C in FIG. 111.

In the machine shown in FIG. 1, a rotor 1 having a central opening is enclosed within a casing cons'sting of two similar Circular end housings 2, 3 connected at their peripheries by a ring housing 4 which comprises a tapered oblique section of a hollow sphere, the end housings being thus relatively inclined to each other. Each end housing has a part spherical face surrounding a central boss with an outer flat transverse face, extending radially from the periphery of said part spherical face, the correspondin-g faces of the housings being presented towards each other. By reason on the inclination of the housings, the axial distance between the faces varies continuously in a circumferential direction between a minimum at the top (according to the figure) of the ca'sing and a maximum at the bottom. Part spherical annular members 5, 6 extend intermediately from the sides of the rotor 1 about the central opening and are generated from the same centre as the part spherical faces of the casing. The annular members 5, 6 bear against the part spherical faces of the casing to isolate within the casing an annular channel bounded by the radially outer peripheries of the annular members 5, 6, the radially inner periphery of the ring casing 4 and the transverse faces of the end housings 2, 3, the latter forming lateral ywalls between the said peripheries of annular members S, 6 and the ring casing 4.

The radially outer portion of the rotor is disposed within the channel in which it moves in the course of rotation.

The central bosses of the end housings contain bearings 7, 8 supporting shafts 9, Iwhich are inclined relative to each other in the same sense as the inclination of the end housings, their axes being normal to the first transverse faces of the respective end housings.

The adjacent ends of the shafts lying within the casing are forked, each having parallel arms extending along either side of the axis of the particular shaft.

Stub shafts 12, 13, 14, (see also FIG. 3) are spaced quadrantrally around the periphery of the central opening of the rotor and extend inwardly along radial axes. Diametrically opposite stub shafts are supported in bearings formed in the ends of the parallel arms of the fork ends of one or the other of the shafts 9, 10, are retained by end caps 11. The fork ends of the shafts 9', 10 are thus disposed at right angles to each other, while each pair of stub shafts constitute trunnions on which the rotor can pivot relative to the appropriate shaft. The stub shafts 12, 14 are conneced to the 'shaft 9 and the stub shafts 13, 15 to the shaft 10, the axes of the respective trunnions and their supporting bearings forming orthogonal diameters of the rotor. Thus, the shafts constrain the rotor to move so that one of these diametral axes rotates in a plane normal' to one shaft while the other rotates normal to the second shaft, the arrangement comprising a varsity of Hooke's joint in which the rotor corresponds to the more usual star member.

The shape of the rotor may be seen from FIGS. 2 and 3. The part spherical annular members S, 6 extending intermediately from the sides of the motor have been mentioned previously. The rotor 1 has a part spherical rim 16 which is centred on the axis of the rotor, and lobes 17, 18, 19, extend radially between the part spherical annular members 5, 6 an dthe rim on opposite sides of the rotor on the same circumferential spacing as the stub shafts 12, 13, 14, 16. Two lobes 17, 19 located diametrically opposite each other on one side of the rotor are circumferentially at right angles to lobes 18, 20 similarly arranged on the other side of the rotor.

With the rotor in place in the casing, as shown in FIG. l, the lobes will bear against the respective lateral walls of the annular channel in the casing, formed by the transverse faces of the end housings 2, 3, and will remain in contact with them during rotation. Between the lobes, the sides of the rotor are shaped so that, during certain phases of rotation at least, there will be clearance between these portions and the lateral walls and the volumes of the chambers so defined will be varied during rotation. When the axis of one pair of trunnion is normal to the axis of both shafts, one chamber will have a minimum volume. As the shafts rotate, the trunnion axes make increasing angles with their original positions causing displacement of the rotor until the next trunnion axis becomes normal to the shaft axes.

In FIG. 1, the lobes on the right hand side of the rotor are in a vertical alignment. When the rotor has been rotated through 90, the lobes on the left hand side will be vertical as indicated in dotted lines at the bottom of the figure. The rotor has apparently moved over to the opposite side of the casing but this is in fact merely illustrative of the displacement of clearance volumes on opposite sides of the rotor caused by the shaping and relative dispositions of the rotor and casing, a maximum volume occurring at one side or the other when the rotor is in the positions described.

Advantage is taken of this by arranging inlet and outlet ports in the casing, the exact positioning depending on whether the machine is to be used as a prime mover or a pump. Operation and configurations obtaining in such circum'stances are described in detail in the aforementioned co-pending prior application, the essential considerations being virtually the same in the case of certain two-cycle machines mentioned therein as in the present case despite differences in the manner of acheiving desired rotor movement.

FIGS. 4 and 5 illustrate some of the factors considered in arriving at the embodiment of the invention described above.

The internal shape of the casing, as may be seen from FIG. 4, is constituted by intersecting portions of two concentric spheres of difering diameters disposed symmetrically about the vertical transverse plane passing through their common centre. Both portions have straight sides, those of the smaller diameter sphere being parallel to the said plane while those of the other are equally inclined to it at an angle a which corresponds to the angle subtended to the longitudinal axis of the casing by the axes of rotor carrying shafts arranged as in the embodiment.

Reference will now be made to FIG. 5 which shows a Hooke's joint having a star member 21 arranged between fork members 22, 23 disposed at right angles to each other on adjacent ends of shafts 24, 25 each of which is inclined at the same angle a mentioned above to the horizontal.

Considering the motion of the star member, its axes are always normal to each other and each axis is constrained to move in a plane normal to the axis of the corresponding shaft. If it be imagined that a cylinder of radius r is carried on each axis of the star member, then a line moving on the surface of one cylinder would touch a fixed plane 26 at a distance r from the centre of the star member and normal with the axis of shaft 24. Similarly, a line moving on the surface of the other cylinder would touch a fixed plane 27 normal to the axis of shaft 25.

By utilising a corresponding spacing for the inclined sides of the larger diameter sphere portion as shown in FIG. 4 (and hence the transverse faces of the end housings 2, 3 shown in FIG. 1), substituting a rotor as previously described for the star member, and shaping the tips of the lobes on the rotor to a part cylindrical profile of radius r, seals can be maintained between housing and rotor during rotation of the latter when line contacts will move arcuately around the lobe tips.

Adequate sealing can thus be maintained between clearance volumes formed between the rotor and the casing without the need for other forms of seal, though simple resilient seals might be used should these be more advantageous in relation to higher working pressures.

FIG. 6 shows a modified form of casing which may be substituted for that in FIG. 1 and wherein the angle between the shafts may be varied to modify the volumes of chambers defined during rotation of the rotor. The casing comprises an end housing 30 similar to the end housing 2 in FIG. l and likewise attached at its periphery to an associated ring housing 31 which again comprises a tapered oblique section of a hollow sphere. In this case however the ring housing is extended in an axial direction (away from the end housing 30) to form a cylindrical sleeve 32 centred on a horizontal axis (relative to the drawing), this axis being inclined to that of the end housing 30. A second end housing 33 has a cylindrical portion 34, which is supported concentrically within the sleeve 32 by ball bearings 35. The end housing 33 has a flat transverse face 36 located within the ring housing 31 and presented towards a corresponding face of the end housing 30. The axis of the face 36 is inclined to that of the cylindrical portion 34 by an angle equal to that between the latter axis and that of the end housing 30 While a journal bearing 37 is provided in the end housing 33 co-axial with the face 36. Rotation of the end housing 33 about the axis of the cylindrical portion 34 has the effect of varying the inclination of the transverse face 36 relative to that of the end housing 30, and also the relative inclination of the journals in the two housings. A l turn from the position shown in full lines in the figure to that indicated by dotted lines will bring the journals into line with one another so that, with a rotor and shafts arranged as in the previous embodiment, no variation of Chamber volume will occur during rotation of the rotor. Intermediate positions give corresponding proportional Variations in rotor displacement and thus the capacity of the machine will be varied. This can be likened to the effect of varying the stroke of a recipro- Cating piston machine.

By the use of two of the arrangements of FIG. 1 coupled together on a common shaft with their outer shafts inclined in the same sense (e.g., either both upwardly or both downwardly to the common shaft), so that corresponding portions of the Channels enclosing the rotors are on the same radial alignment relative to the common shaft, thrust loads and inertial loads can be conveniently balanced. The end loads on the rotors will oppose each other and couples due to the rocking motion of the rotors will cancel each other out. Thus, the use of large thrust bearings and the possibility of a secondary balancing shaft can be avoided.

Such a machine intended for use as an air Compressor is shown in FIGS. 7 and 8. Two rotors 40, 41 (FIG. 8), generally as that shown in FIGS. 2 and 3 though differing somewhat in configuration as will be detailed later, are enclosed within casings 42, 43 containing annular channels through which the radially outer portions of the rotors move in the course of rotation. A shaft 44 supported in a housing 45, which housing extends between the casings 42, 43, is forked at both ends. The fork ends both lie in the same axial plane and each engages a pair of diametrically opposed stub shafts in one of the rotors, the said stub shaft being arranged around the peripheries of the central openings of the rotor discs as previously described. Pairs of stub shafts 47, 48 in each rotor (see also FIG. 11) are arranged at right angles to those just mentioned and are engaged in one case by fork ends formed on a shaft 50 and in the other case by fork ends formed on a shaft 51, the shafts 50, 51 extending on opposite sides of the respective rotors to the shaft 44. The shafts 50, 51 are supported in housings 52, 53 so that their axes are inclined upwardly (according to the drawing) relative to that of the shaft 44 and by the same angle. Air inlet passages 54, 55 extend through the casings 42, 43 to communicate With the Channels therein near their widest points. The passages terminate in the channel walls as ports Which are so shaped that portions will be uncovered by the rotor rims during certain stages of the rotation of the rotors to admit air to Chambers defined between the rotors and their casings. Outlet passages 56, 57 extend through the casings from ports located on the peripheries of the Channels at the points where their two inclined faces are closest together. The ports last mentioned are uncovered during other stages of the rotation of the rotors and air which has been compressed by variation in volume of the abovementioned Chambers during rotation of the rotors will pass to the outlet passages.

It is desrable that the outlet port be located in the region where the Working fluid (air in this case) is at maximum pressure (i.e., where the lateral walls of the channel are closest together) and for this reason the circumferential extent of the port relative to the channel should be limited. The provision of adequate port area requires the widest possible opening in an axial direction, leading in turn to rotors with comparatively wide rims. To avoid an unduly heavy and bulky construction the radially outer portion of a rotor is preferably tapered inwards towards the center. As a result the lateral walls of the Channel become of conical form rather than flat as previously.

FIGS. 9 and 10 show diagrammatically a casing (such as 42, 43 in FIG. 8) from Which it may be seen that side surfaces 60, 61, which form the lateral walls of an annular channel, comprise two truncated right Circular shallow cones of semi-included angle q with their axes intersecting on the centre line of the casing and inclined relative to each other at angle The periphery of the channel in the casing is constituted by a spherical surface of radius R joining the outside edges of the side surfaces, the hatched area P thereon indicating the extent of the outlet port. The shape and location of the inlet port is indicated by the hatched area T. (N.B. the casings 42, 43 have inner part-spherical faces as in the earlier embodiment-these are not shown in FIGS. 9 and 10.)

The elevation, the rotors 40, 41, one of which is shown in FIG. 11, resemble that of FIG. 3 in having a central opening which is partly enclosed by part spherical annular members 66, 67 (see also FIGS. 12 and 13) extending intermediately from each side. Stub shafts 46, 47, 48, 49, already mentioned, for engagement by the fork ends of appropriate shafts, are spaced quadrantally around the periphery of the central opening, and two diametricallyopposed lobes 68, 69 extend radially across each side of the rotor, those on opposite sides being relatively displaced by In order to mate properly with the casing, the side surfaces of the radially outer part of the rotor are each composed of parts of four cones.

Two dametrically-opposed part cones have the same semi-included angle (p (see FIG. 12) as the side surfaces of the casing and their axes are similarly inclined. The remaining portions of the particular surface are parts of cones that are tangential with the first pair and co-axial with one pair of stub shafts (e.g., 46, 47). The semiincluded angles of these cones,

The surface shape of the other side of the rotor is the same but rotated through 90 so that the cones of semiincluded angle 4 1 are co-axial with the other pair of stub shafts (48, 49).

Since the rotor rim would otherwise eifectively shroud Chambers formed at the sides of the rotor from an outlet port located as in FIGS. 8, 9 and 10, a portion of the rotor periphery adjacent to each lobe is cut away on that side of the rotor on which the lobe is formed to form pockets 70 which extend partially through the rotor rim and serve primarily to connect Chambers defined between the side surfaces of a rotor and the lateral walls of the annular channel of its associated casing with the outlet port in the casing during appropriate stages of rotor rotation. The rim itself is a part spherical surface centered on the center line of the rotor.

Surfaces of almost any body of revolution may be used in place of conic surfaces if desired provided that these permit of proper correspondence between rotor and casing.

In the operation of the mechanism as a Whole, each side of a rotor and its co-operating casing surface may be regarded as an entity, the two parts eifectively acting independently of each other. As the rotor rotates, its rim passes over its respective inlet port to connect the associated inlet passage with a chamber-formed between the rotor and the casing when the volume of the Chamber is increasing and air is accordingly drawn in. With further rotation, the port is closed off, after which the volume begins to decrease and the air becomes compressed. In due Course, the cut away portion in the rotor rim passes over the outlet port when the air flows out. The length and width of outlet ports and of the cut away portions are largely determined by the designed pressure ratio and mean delivery air velocity respectively. The shape of the cut away portions fixes the clearance volumes of the Chambers and consequently the opening time of inlet ports. The profiles of the opening edges of the inlet ports therefore conform to those of the leading edges of the cut away portions at such times as clearance volumes have been expanded to inlet pressure. The profiles of the closin g edges of the inlet ports are fixed by the line of the respective rotor edges at the positions corresponding to maximum chamber volumes.

The arrangement of casing shown in FIG. 6 whereby the angle between the shafts connected to individual rotors may be varied is also applicable in this case.

In a machine used as a motor rather than as a compressor, the function of the ports is reversed, viz. inlet ports become outlet ports and vice versa, their positioning relative to the annular channel being unchanged or substantially so and the relative pressures of working fluid being the same as previously (i.e., fluid pressure at a port located where the walls of a channel are closest together will be higher than at a port disposed where the walls are further apart).

When running at the high speeds at which normal operation would be expected to take place, clearances between corresponding surfaces of rotors and casings of machines according to the invention can be such that leakages would be contained within acceptable limits without the need for contact seals. However, flexibility of shafts and bearing, thermal and other distortions make it virtually impossible to maintain appropriate clearances under all running conditions, particularly towards the low end of a speed range. The arrangment of these machines is such that systems can be envisaged which involve the use of seals in rubbing contact at low speeds, when wear rates are low and leakage rates generally unacceptable, but can be retracted according to conditions.

Such seals may be used between the corresponding part spherical surfaces of rotors and casings and at the peripheries of rotors.

I claim:

1. A rotary piston machine comprisng a casing, two shafts mounted for rotation in the casing and inclined relative to each other, a rotor pivotally connected to the shafts about orthogonal diametral axes in such manner that the shafts constrain the rotor to move so that one diametral axis rotates in a plane normal to one shaft and the other diametral axis rotates in a plane normal to the second shaft, an annular channel within the casing bounded in part by two lateral Walls set apart from each other at a distance which varies contnuously circumferentially in relation to the channel, an annular part of the rotor contained within the channel, the radially outer portion of the rotor reduced in cross-section from its periphery inwardly towards the center of the rotor and constituting the said annular part, ports for the entry and exit of a working fluid provided in the channel, whereby in operation fluid passing through one port is at high pressure compared with fluid passing through another port, the high pressure port located in the periphery of the channel where the lateral walls are closest together.

2. A rotary piston machine according to claim 1 including trunnions which connect the rotor to the shafts.

3. A rotary piston machine according to claim 1 provided with annular members extending from the sides of the rotor to cooperate with the casing to isolate the channel within the casing.

4. A rotary piston machine according to claim 3 in which the annular members are part-spherical and the casing has similar surfaces disposed in contact therewith.

5. A rotary piston machine according to claim 3 in which the radially outer portion of the rotor is provided 8 with radially-extending lobes in its side surfaces, which lobes bear against the lateral walls of the channel during rotation of the rotor.

6. A rotary piston machine according to claim 5 having two diametrically-opposed lobes' extending radially across each side of the rotor and the lobes on opposite sides of the rotor are relatively displaced by 90.

7. A rotary piston machine according to claim 1 in which portions of the rotor periphery are cut away to afford communication between the annular channel and the high pressure port according to the rotation of the rotor.

8. A rotary piston machine according to claim 1 in which the lateral walls of the annular channel are of conical form.

9. A rotary piston machine according to claim 8 in which the lateral walls comprise two similar truncated right circular shallow cones with their smallest diameters directed towards each other and with their axes relatively inclined, and the side surfaces of the radially outer part of the rotor are each defined by two pairs of diametrically-opposed part cones compatible with the said truncated cones and with their axes similarly inclined.

10. A rotary piston machine according to claim 1 in which the casing comprises two parts which are rotatable relative to each other and arranged so that the angle between the shafts is varied by such rotation.

11. A rotary piston machine according to claim 1 comprising a further rotor of similar form which is pivotally conected about a diametral axis to one of the shafts aforesaid at the other end of said shaft, a third shaft, and said rotor pivotally connected about the orthogonal diametral axis to said third shaft which is inclined relative to the shaft last aforementioned, an annular part of the further rotor being contained in like manner to the other rotor within an annular channel bounded in part by two lateral walls set apart from each other at a distance which varies contnuously circumferentially in relation to the channel.

12. A rotary piston machine according to claim 11 in which the pivots about which the rotors are connected to the same shaft have their respective axes in the same plane.

13. A rotary piston machine according to claim 12 in which the axes of all the shafts are contained within the same plane as each other and the axes of the shafts connected to separate rotors only are symmetrically inclined to the axis of the shaft connected to both rotors about a transverse plane extending through the mid-point of the sgat last mentioned and normal to the axis of that s a t.

References Cited UNITED STATES PATENTS 297,589 4/1884 Enke 91-85 324,246 8/1885 Fielding 91-69 1,968,l i 7/1934 Schnurle et al. 103-117 2,475,096 7/1949 Holl 230-142 2,727,465 12/1955 Dutrey 103-117 MARK M. NEWMAN, Primary Examner W. J. GOODLIN, Assistant Examner U.s. cl. X R. 418-.215 

